1. Field of the Invention
The present invention relates to a combustion generating device of an internal combustion engine, and more particularly, to a combustion generating device of an internal combustion engine, which directly injects a flame into a combustion chamber, the flame being ignited and generated at the same time as a mixture of air and fuel is injected from a sub injector which mixes the air and fuel and injects the mixture.
2. Description of Related Art
In general, an internal combustion engine using gasoline as fuel, such as an engine of a vehicle, directly injects fuel into a combustion chamber formed in a cylinder block through an injector, and the fuel injected into the combustion chamber is burned by a flame generated through an ignition system, for example, a spark plug.
In the internal combustion engine having the above-described structure, the size of a flame kernel formed by a spark of the spark plug is small, and the duration thereof is short. Therefore, the fuel mixture within the combustion chamber may not be completely burned. During lean burn (ultra lean) combustion for improving fuel efficiency, a large amount of nitrogen oxide is generated by high-temperature combustion. Therefore, the internal combustion engine requires an expensive catalytic filter to reduce the nitrogen oxide.
In order to overcome such a defect, a prechamber jet ignition system is used. The prechamber jet ignition system enables low-temperature rapid combustion during ultra lean combustion of fuel within the combustion chamber, thereby reducing the amount of nitrogen oxide. Further, the prechamber jet ignition system may continuously and stably generate a very large flame kernel. The prechamber jet ignition system includes a prechamber formed above the combustion chamber and communicating with the combustion chamber, a sub injector installed to inject fuel to the prechamber, and a spark plug for igniting fuel within the prechamber.
Accordingly, after a mixture is introduced into the combustion chamber or fuel is injected through an injector, a small amount of fuel is injected into the prechamber through the sub injector, and the spark plug generates a spark inside the prechamber so as to ignite the fuel within the prechamber. The flame ignited in such a manner is injected to a fuel chamber from the prechamber, and the fuel within the combustion chamber is burned by the flame injected from the prechamber.
However, in the above-described internal combustion engine where combustion is performed in the combustion chamber through the flame injected from the prechamber, an accidental fire is highly likely to occur when an ultra small amount of fuel is injected into a small space formed by the prechamber and ignited by the spark plug. In this case, the engine may be failed. Further, since the air within the prechamber is not fresh external air but exhaust gas remaining in a previous explosion stroke, the prechamber contains a small amount of oxygen. Accordingly, the combustion inside the prechamber is destabilized. In addition, the internal combustion engine has difficulties in performing precise ignition control such as air-fuel ratio control or combustion speed control.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.